The iris
To create the iris, we're going to use a mesh torus (the donut shape).
Just make it any size you want. We can scale it later. In the timeline,
name it "Iris," then follow these steps.

1. First we're
going to increase the resolution of our mesh torus. If you don't do
this, you're going to have some flat edges that will show up in your
final render. So just click on the tool that's called MeshMan Quad.
Then click on your mesh torus. This will double your polygon count
for that object only. (Incidentally, you can also do this to portions
of an object by using the mask tool, as discussed in a previous
tutorial.) Important: After you've used this tool, select
another tool so that you don't accidentally use it again. Increasing
polygons can cause a significant slowdown in performance.

2. Go into the
FX mode by selecting FX from your menu bar. Select the effect called
Normal Displace. Apply it to your "Iris" until it's big
and fat, and there's just a little hole in the middle.

4. Now head over
into the Material mode. For Diffuse Color use the texture you created
in Photoshop (the one we called "iris1.tif"). Leave it at
100 percent.

5. For Specular
Color, Specular Roughness and Bump, select the desaturated texture
you created called "irisbump1.tif. Leave all of these at 100
percent as well. Leave everything else at default values.

6. Now, you might
have noticed that the texture doesn't look exactly right. So go into
the mode called Mapper by clicking the Mapper button in the top menu
bar. Then select the tool called "Apply Planar," and click
on your object. You might also need to use the Scale and Drag tools
to fit it just right.

The pupil
The pupil will be a very simple process. Create a mesh sphere about
half the diameter of the "Iris." Then follow these instructions:

1. Go into FX
mode and flatten the sphere, just as we did above.

2. Go into the
Material mode and set the Diffuse Color to Black. Leave everything
else at default values. That's it.

Putting
it all together
So now we have an eyeball that's pretty much together.

Parenting
All we have to do is attach the "Iris" and "Pupil."
Using tools in the composer, rotate the "Iris" and "Pupil"
so that they'll be flat against the indentation we made in the "Inner"
object. (To make this process easier, you should temporarily hide
the "Outer" object by clicking its Hide button in the timeline.)
You'll also want to scale the "Iris" to fit flush against
the edges of the indentation of the "Inner" object. Make
sure that no part of the "Iris" intersects the "Inner"
object, as it will be quite obvious in the final render.